Does the behaviour of the pedestrian require you to use the horn?

Why?

The pedestrian is using the marked crossing, so you must give way. Their behaviour does not call for a warning with the horn. In a built-up area, you may sound the horn only when necessary because of immediate danger.

art. 26 ust. 1 oraz art. 29 ust. 2 pkt 2 Prawa o ruchu drogowym